Process of refining animal and vegetable oils



April 30, 1940. CLAYTON 2,199,041

PROCESS OF REFINING ANIMAL AND VEGETABLE OILS Filed Aug. 1, 1939 Patented Apr. 30, 1940 UNITED STATES PATENT OFFICE Q PROCESS OF REFINING ANIMAL AND VEGETABLE on.s

Benjamin Clayton, Houston, Tex., assignor to Refining, Inc., Reno, Nev., a corporation of Nevada Application August 1, A

26 Claims.

. a relatively concentrated solution of a strong acid or alkali or may be weak solutions thereof or solutions of weak alkalies or acids or of neutral salts oreven water alone. When refining edible oils the refining reagent employed is usually an aqueous alkaline solution. A caustic soda solution is ordinarily employed, since such a solution has been found to be particularly effective in reducing the color of the oil. Alkaline reagents react with free fatty acids in the oils to form soap. An excess of refining agent over that.

necessary to neutralize the fatty acids is employed to react with gums and coloring matter to render the same separable-with the soap. The mixture of reaction products is commonly referred to as soapstock or foots. Any unreacted refining reagent also separates with the ,soapstoek to leave substantially neutral oil. The reactions with impurities and subsequent separation of the reaction products from the oil reduces the'total amount of the original oil and produces an'unavoidable refining loss.

The alkaline reagent will also react with the neutral oil to produce soap. This reaction is slower than the reaction with impurities but in prior refining processes, particularly the con- 1 ventional batch refining operations wherein the oil and alkali are kept in contact over extended periods of'time under conditions which promote 'the saponification of neutral oil, large quantities of neutral oil are converted into soap and separated with the much less valuable soapstock. Also in conventional processes considerable quantities of neutral oil are ordinarily entrained in the separated soapstock. The saponification of neutral oil and the entrainment thereof in the soapstock produce refining losses which can be to a large extent eliminated by the present invention such-that the total refining loss is markedly reduced.

While the invention is particularly adapted to the refining of edible oils with alkaline reagents, any reagents, for example, water or relatively dilute solutions of electrolytes attack or cause hydrolysis, sulfuration, chlorination, etc. of neutral oil at elevated temperatures. The character of the attack upon the oil will depend upon the- 1939, Serial No. 287,856

temperature and time. After the mixture of oil and reagent has once been subjected to the high temperatures to break any emulsions present therein the mixture may be immediately cooled so as to reduce attack upon the oil and preferably give a low temperature treating step prior to separation. Impurities precipitated by the refining reagent whether it be acid, alkali or water alone agglomerate with each other, for example,

color impurities are adsorbed by, precipitated 10 v gumsor soapstock, and rendered more easily separable. Because of the low temperature attack on the neutral oil by the reagent is. minimized. Also, the mixture having once been heated to a relatively high temperature it is many times possible to effect successful separation at the low temperature without reheating.

It is, therefore, an object of the present invention to provide a process of refining vegetable and animal oils by which refining losses are markedly reduced.

Another object' of the invention is to provide a process in which refining losses due to destruction of neutral oil and entrainment thereof in the separated foots are minimized.

Another object of the invention is to provide a refining process in which the temperatures L during the process are controlled in a manner to markedly reduce the refining losses;

Another object of the present invention is to mix the oil and refining reagent at' a temperature sufilciently high to prevent the persistence of a stable emulsion and thereafter immediately cool'the mixture to minimize refining losses due to s'aponification of the neutral-oil.

Another object of the invention is to immediately break or prevent the formation of the emul-- sion which tends to form when oil and an alkaline solution are mixed and thereafter provide sufllcient, time of reaction at'a low temperature to reduce the color of the oil without substantial saponification of neutral oil; 4

A still further object of the invention is to provide a continuous process for refining animal and vegetable oil in which the temperatures of the materials being processed are rapidly changed in order to minimize refining losses-due to both the saponification of neutral oil and the entrainment of neutral oil in the separated soapstock.

In batch refining it was known that heating the oil much above room temperature (75 to 80 F.) before adding the refining reagent would often set the color in the oil, particularly with highly colored oils, such as cottonseed o'il, render- 1 ing its subsequent removal difficult or impracticable. The refiner, therefore, found it necessary to mix the oil and refining reagent at a relatively low temperature, not appreciably above room temperature.

When an alkaline solution is mixed with an oil containing free fatty acids at such low temperatures, an emulsion, which is apparently of the water in oil type and which is stable against settling or centrifugal separation, is almost instantaneously produced. In such an emulsion the alkali is in extremely intimate contact with the neutral oil and saponification thereof is quite rapid despite the low temperatures. Continued agitation or mixing will somewhat destabilize the same to cause a pin break but the resulting emulsion does not completely break at the low temperature and does not separate. The refiner has heretofore found it necessary to heat the emulsion to a temperature suflicient to substantially completely destabilize or break the emulsion. Increasing the temperature accelerated the attack on the neutral oil and as the heating could not be accomplished rapidly with large batches of oil, large refining losses resulted. When an emulsion breaking temperature was reached and the emulsion broken, the less intimate contact of the alkali with the neutral oil retarded the saponification thereof during the separation step.. This effect was largely overcome by the necessary increase in temperature. The emulsion breaking temperature depends upon the particular oil being treated. For high quality oils containing small amounts of impurities such temperatures may be as low as or F. while with extremely pooroils, containing large amounts of impurities, such temperatures may be as high as to F. or even higher.

Reduction of color ordinarily requires more time of contact than that necessary for neutralization and apparently also requires, after the emulsion is broken, adsorption of or combination with the soapstock of reacted color im-. purities in order to effect separation thereof with the soapstock. In the batch process sufficient time was provided for removal of color impurities during heating and settling so that no additional reaction period was necessary for this purpose.

In accordance with the present invention, the oil and refining reagent are mixed at a temperature at least as high as the emulsion breaking temperature of theparticular oil. This'is preferably accomplished by rapidly heating small quantities of the oil suflicient to produce a mixture at the requisite temperature and then immediately mixing it with a properly proportioned amount of refining reagent before setting of the color is produced. Alternatively the refining reagent may be heated sufliciently high such that the temperature of the oil is raisedduring admixture at least to the emulsion breaking temperature for the particular oil. Also both the oil and refining reagent can be heated so that the requisite temperature of .the mixture is produced. The temperature of mixing is preferably not subsantially higher than that necessary to break the emulsion. Such a continuous method,

providing for the preheating of one or more of the admixed materials, is shown and-claimed in- Clayton et al; Patent No. 2,100,275.

When small quantities of the oil and alkaline refining reagent are thus mixed, the saponification of the fatty acids is substantially instantaneous. Emulsions of the type formed during mixing at room temperatures, are not formed factory separation is obtained.

or, if formed, are almost instantly destabilized or broken. Thus any emulsion of the type which promotes reactions with neutral oil is either not formed or is transitory only. The relatively high or emulsion breaking temperature does, however, promote saponification of neutral oil. It has also been proposed in my joint Patent No. 2,100,274 to provide such a rapid, continuous operation in which the mixture is heated to break the emulsion and to condition the same for centrifugal separation.

Applicant has found that color reactions and combination of the reaction products thereof with the soapstock will go forward, after the emulsion is broken in the manner proposed by either of the aforesaid patents, even at temperatures below that at which substantial saponification of neutral oil occurs. The present invention, therefore, contemplates rapidly cooling the mixture of oil, excess alkali, and soapstock resulting from the mixing operation, as soon as practicable after mixing. By mixing and then cooling rela-., tively small quantities this can readily be accomplished. The mixture is cooled to as low temperature as can be employed without solidifying or increasing the viscosity of the oil below a flowable condition. With many vegetable oils, such as cottonseed or soya bean oil, this temperature may be as low as room temperatures (75 to 80 F.) or even lower while with certain animal oils undesirable solidification of saturated fats may occur and less cooling must be employed. Sufiicient time of treatment at the low temperatures is provided to secure the desired color reduction. The time necessary will vary with different oils and the amount of color reduction required and no time applicable to all oils can be given. The necessary time may be less than one minute and may require five minutes but will rarely exceed this period, although with exceptionally hard oils to decolorize periods as'long as ten minutes or even longer may be I required. 7

During the color reduction period the mix- 7 or agitation may cause the \soapstock particles to be broken up and dispersed in the neutral oil to such an extent as to render separation difiicult.

While gravity separation of the soapstock from the neutral oil may be employed, such separation is slow and substantial reaction with neutral oil cannot be prevented if the time necessary for settling is provided. Again raising the temperature of the oil speeds up the settling action but this increases saponification of neutral oil. Substantial savings are effected by the esses even if separation by settling is employed Y but the invention produced markedly improved results when centrifugal separation is employed both as to reduction of losses due to saponification of neutral oiland the reduction of entrainmentin the separated soapstock.

- Effective centrifugal separation can many times be. effected at the low temperatures employed during the 'color reduction step and this low temperature separation is preferred if satis- However, increase in temperature reduces the viscosity of the oil and softens the soapstock so as to facilitate centrifugal separation.

By employing the heated centrifuge disclosed in my copending application, Serial No. 34,258, filed August 1, 1935, now Patent No. 2,100,277, granted November 23, 1937, the temperature of the soapstock and oil can in most instances be rapidly increased sufficient to give proper separation by contacting steam or other gaseous heating'mediums with the outer walls of the bowl. In lieu of employing the heated, centrifuge the mixture maybe rap- 1 idly heated in small quantities before introduction to the centrifugal or both heating prior to introduction into the centrifugal and the heating of the centrifugal can be advantageously employed. The mixture should be as rapidly heated and maintained in the'heated condition for as -short time as practicable so as to prevent substantial saponification of neutral oil. The .cen- I trifu'gal separation removes substantially all of the refining reagent from contact with the neutral oil so that continued saponification of neutral oil after separation is substantially prevented. However, it is within the contemplationof' the present invention to wash and vacuum dry the oil or to clarify the same with clarifying agents, such as fullers earth, immediately after separation to remove small amountsof residual alkali, water and other deleterious impurities.

The temperature for effective centrifugal separation will vary with the type of oil being treated. In many instances it will be lower than the emulsion breaking temperature employed during mixing but may vary from approximately 75 to 140 F. although temperatures between approximately 100 and 130 F. will ordinarily be found practicable.

While the-process described above may be effectively carried on by employing small batches of oil, say, for example, 500 to 1000 poundsjof oil, as contrasted with the usual "batch practice employing 60,000 pounds of oil, in apparatushavferred apparatus, and

Figure 2 similarly illustrates a preferred ap- 'paratus.

Referring more particularly to the drawing animal or vegetable oil may be withdrawn from a source of supply, shown as a tank l0, by a proportioning pump II and forced through a heating -coil .|2 to a mixer l3. Similarly a refining reagent, such .as an alkaline solution, ay be withdrawn from the tank by a propor iqning pump l6 and forced through a heating coil l6 to. the mixer l3. The temperature of the oil in the 'tank or if a solid fat is'being treated the temperature ofthe material in the tank |0 may be such as to render the same fluid so that it may 'be handled by the pump Pumps II and I6 deliver substantially constant and properly Proportioned streams of the oil and refining reagent to the mixer l3 and may be driven by a variable;

speed motor II with a variable speed device I! positioned between the pumps so that the relaf tive proportions of fat and reagent maybe varied by adjusting the variable speed device l8 and the total amount of oil and alkali varied by adjusting the speed-of the motor H. The particular proof mechanical mixer.

portioning device, shown is merely for purposes of illustration as any suitable type of proportioning apparatus may be employed.

Heating coils l2 and I6 may be surrounded by casings I9 and 20 so that any suitable heating medium, such as steam, hot water or heated mineral oil, may be circulated therethrough. The rate of flow and temperature of the heating medium should be correlated with the rate of flow of oil or reagent in the coils |6 so the tem- 1o peratures of the materials flowing through the coils |2 or I6 are'rapidly raised to a predetermined temperature depending upon the oil being refined. As before indicated, either the oil or reagent or both may be preheated so that'the mixture is formed at or above an emulsion breaking temperature.

By mixing relatively small streams of oil and alkali solution in flow in the mixer l3, the free fatty acids are rapidly neutralized to form soapstock. This mixer preferably injects a stream of one material into the other but may be any type The mixture leaving the mixer l3 consists of neutral oil in which are suspended particles of softened soapstock which could be separated from the neutral oil to produce a clean separation by delivering this oil directly to a centrifugal separator. -If substantial color reduction is desired, the mixture is immediately and rapidly cooled'and the color reactions allowed to take place at a temperature below that at which substantial saponificationof neutral oil occurs. This can be done by passing the mixture through a pipe 20 and a cooling coil 2| positioned in a casing 22 through which any desired cooling medium can be circulated. Cold water, such as ice water, may be employed as the cooling medium or ice can be charged directly into a body of water in the casing 22. Preferably a more rapid cooling medium such as liquid carbon dioxide, ammonia or other refrigerating medium, is introduced into the casing 22 so that this casing becomes the evaporator of a refrigerating system. That .is, evaporated revfrigerating medium may be withdrawn through 5 the pipe 23, compressed, cooled to liquid condition and again introduced into the casing 22 through a pipe 24. The'rate of cooling of the mixture flowing through the coil 2| should be carefully correlated with the temperature of the cooling medium so that the mixture is cooled to a predetermined temperature, depending upon the type of soil being treated. The cooled mixture may be discharged from the coil 2| through a pipe 26 and passed throughtreating coils 26 and 21 in order to give suflicient time for color reduction. This time will alsodepend upon the oil being treated and in-some instances the time required for passage through the cooling coil 2| may be sufficient, in which case the mixture may be by-p'assed around the coils 26 and 21 by thepipe 26 or in.other1cases. coil 26 only may be employed by by-passing coil 21 by means of pipes 26 and 20. Thus, a time of treatment at the lower mixture is delivered to the treating chamber by the pipe and kept in motion in the chamber by means of an agitator 3| driven from any suitable source of power through a pulley 32. Sufficient motion is given to the mixture in the chamber to minimize stratification and provide the repeated contacting above described but the agitation is kept below that at which the particles of soapstock are broken up and beaten back into the oil to form a difiicultly separable emul The treated mixture from any of the coils 2|, 26 or 21 or the chamber 30 is'delivered by a pipe 33 to a heating coil 34 positioned in a casing 35 through which any desired heating medium may be circulated. The temperature of the mixture is rapidly raised in the heating coil 34 to a temperature which provides best separation for the particular oil being treated. It is then delivered by a pipe 36 to a centrifugal separator indicated at 31 wherein the soapstock is separated from the refined oil. The soapstock is discharged through a pipe 38 into a soapstock receptacle 39 and the separated refined oil discharged through a pipe 40 into an oil receiver 4|.

The centrifugal 31 is preferably of the heated type in which the rotating bowl of the centrifugal is heated by steam or other gaseous heating medium. The applied heat causes the soapstock to be delivered continuously from the bowl of the centrifugal and in many cases sufficient heat can be supplied to the bowl to raise the temperature of the materials therein suflicient that the heating coil 34 may be eliminated. Also instead of employing the heating coil 34 it is-within the contemplation of the present invention to introduce a stream of hot water, steam or other heating medium directly into the mixture just before or inthe centrifugal to heat the mixture to a proper separating temperature.

The materials are preferably maintained out of contact with the atmosphere during the entire process and are forced through the system under superatmospheric pressure by the pumps H and I5 although supplemental pumps may be employed in the system if necessary to overcome frictional resistance to flow. Since the mixture leaving the mixer I3 is in a separable condition,

- subjected to gravity separation by discharging the same into a settling'tank but the high temperature promotes sapon'ification of neutral oil during settling of the heated mixture and the entrainment of neutral oil in the soapstock is much higher than is the case when centrifugal separation is employed. Also, the mixture leaving.

rapidly cool the mixture and then rapidly heat I the mixture with immediate centrifugal separation thereafter.

As pointed out before, the heating in coil l2,

the cooling in coil 2| and the heating in coil 34 or in the centrifugal separator should be as rapid as possible.

of cottonseed oil can be passed per minute 1 through a system in which the coils and connect As a specific example, 16 pounds ing pipes are approximately three-quarters of an inch in diameter. This amount of oil can be However, such separation by gravity trifugal separation.

tating or partial refining agents as alcohols or solvents for the oil in which gums or other imheated in the coil |2 to a temperature of F. within one minute or less or it can be heated substantially instantaneously in the mixer l3 by supplying an alkali solution to the mixer at a temperature considerably above 135 F. Mixing and neutralization of the free fatty acids takes place substantially instantaneously and the mixture can be delivered to the coil 2| within a few seconds. The temperature can be dropped in the coil 2|. to 70 F. in one minute or less, and again heated to 135 F. in the coil 34 in approximately the same time. The time provided in the coils 2| -and 34 may, with a light colored oil, be sufficient to secure the necessary color reduction in which case the coils 26 and 21 can be by-passed. If more time is needed, coils 26 and 21 can be employed and the necessary time of treatment for color reduction thereby obtained. Such time of treatment will rarely exceed five minutes and at most not more than ten minutes, such that the entire process may easily be formed in con- 7 siderably less than fifteen minutes even with a diificult oil to treat. While a time of one minute for heating in the coils l2 and 34 and cooling in the coil 2| has been givenby way of example,

' it is apparent that these temperature changes ing can many times be employed as the formation of an emulsion in the mixer |3 can be minimized at a lower temperature, thus producing less saponification of neutral oil. Inhibitors, such as ethyl, isopropyl or similar alcohols, or their esters, reduce the viscosity of the mixture at the lower temperature in the coils 26 and 21 or pipe 28 such that a lower temperature can be employed therein or such that the color reactionsand adsorption go on at a higher rate thus decreasing the time of treatment at the lower temperature. Also separation can many times be effected at a lower temperature in the centrifugal 31 such that saponification of neutral oil is reduced and also a cleaner separation effected to leave less neutral oil entrained in the soapstock delivered into the receiver39.

I have found that the present invention is also applicable to the refining of degummed oil. Such oil has been previously treated by a partial refining'process'to remove all or a portion of the gums, for example, by mixing small amounts of a degumming reagent such as water or very dilute solutions of acids, salts or alkalies with the oil to precipitate gums and then separating the precipitated material from the oil by settling or cen- Also other gums precipipurities are insoluble may be employed as partial refining reagents. The removal of the gums prior to alkali refining results in an entirely different character of soapstock due to the partial or substantially complete absence ofgsuch gums in the soapstock. Considerable difiiculty is frequently encountered'in securingeffective separation. Effective separation can be secured by employing the present process either with or without the employment of a saponification and entrainment inhibitor such as described above, although such an inhibitor reduces'refining losses due to saponification of neutral oil and entrainmentof the same in the soapstock.

The continuous process herein disclosed can be advantageously combined with a continuous degumming process. In such a continuous degummin g process a small proportion, for example, 1% to of water or other degumming reagent is mixed with the oil, preferably in a continudus mixer, to precipitate gums and the precipitated material promptly separated from the oil by centrifugal separation. As subjecting the mixture to elevated temperatures at some point prior toseparation facilitates the separation, the oil may be preheated before mixing the reagent therewith or the mixture subsequently heated either before or during centrifugal separation or both to a temperature which will break any emulsion which may form or tend to form. In either case the heating is performed as rapidly as practicable and the elevated temperature maintained for a brief period to avoid setting of to 80 to 100 F. for a short treating time not only allows the precipitated gums to reach a more easily separable condition and adsorb color impurities from the oil, but reduces hydrolysis of neutral oil and prevents setting of the color in the oil which latter action frequently occurs during degumming operations to render the color dimcult to remove in subsequent refining or bleaching operations. The separation of the precipitated gums is preferably carried on at as low temperature as practicable but it may be necessary to reheat the mixture, in which case, the oil leaves the degumming centrifugal at an elevated temperature and is in condition to be immediately mixed with an alkaline refining reagent. If necessary, additional heat may be supplied to the oil before mixing with the alkaline refining reagent. Such a combined process produces purer soapstock, utilizes the heat necessary-in the degumming operation in the refining operation, and avoids the necessity of removing small quantities of degumming reagent left in the oil by the degumming centrifugal, if the oil is stored after degumming.

Thus the present invention provides for heating the oil at a rapid rate and the maintenance of the oil at a high temperature for an extremely short period of time so that there is no substantial setting of color in the oil. Mixing at a relatively high temperature in the mixer l3 prevents or immediately breaks any emulsion which favors the saponification of neutral oil and such saponification is therefore reduced. Also the mixture of oil and alkali is kept at a high temperature for an extremely brief period of time such that saponification of neutral oil is further reduced, Any period of contact between neutral oil and alkali necessary for color reduction takes place at a relatively low temperature suchthat no substantial .saponification of neutral oil is effected during the color reduction step.

It is sometimes found very diflicult to reduce the color of a particular oil, in which case it is substantially increasing the losses.

possible to greatly increase the excess caustic ordinarily employed without appreciably increasing refining losses. Thus in some instances the excess may be substantially doubled in order to speed up color reactions but, because of the short period in which the toil and alkali are in contact and the low temperature during most of this period, the amount of neutral oil saponified is of the process is thereby prevented. The entire process can thus be performed in a few minutes and avoids any extended period of contact between the oil and reagent.

The invention has been described with particular reference to the refining of animal and vegetable oil with an alkaline refining reagent but the steps described are also applicable to acid refining of oils such as drying oils, since the acid reagents employed also attackthe oil itself at the higher temperatures. Such acid refining processes involve the treating of the oil with acids of sufficient strength to act upon gums, coloring matter, other impurities to precipitate the same and render them separable from the oil. The drying oils, such as linseed orsoya bean oils, to be used for certain purposes in the paint and varnish industries are treated with from one-half to one and one-fourth percent of'relatively strongacid, for example, 60 .86. sulfuric acid, to render impurities separable from the oil. Other acids, such as hydrochloric, may be employed and such acids will attack neutral oil as well as impurities therein. For example, sulfuric acid willsulfonate the oil while hydrochloric acid will chlorinate the same. Sulfuric acid is ordinarily used and any sulfonation of the oil is deleterious as among other things, it causes the oil to further discolor when heated for the purpose of bodying the same.

By employing the process of the present invention, in which the mixture is cooled immediately after being subjected to elevated temperatures, the mixture may be rendered separable and given a treating time for agglomeration of im-. purities and color adsorption yet the mixture is subjected to an elevated temperature for such a short period of time that attack on the oil is minimized. Effective separation can in many cases be accomplished at the lower temperatures but if necessary, the mixture can again be rapidly heated and immediately separated without In general, the temperatures and times of treatment as well as the manipulative steps of the process are substantially the same as for alkali refining of vegetable and animal oils. The term animal and vegetable oils is intended to include fish oils and analogous oils. v

This application is a continuation in part of my copending application Serial No. 167,067, filed October 2, 1937. .jWhile I have disclosed the preferred embodi-- ,ignents of my invention it is understood that I,

not to be limitedto the details thereof and of the following claims.

What I claim is:

l. The process of refining animal and vege-.

table oils containing free fatty acids and coloring matter, which comprises, mixing an alkaline refining reagent with said' oils at a temperature sufficiently high to prevent the formation of a stable emulsion, whereby. said free fatty acids are substantially completely neutralized and a separable mixture of oil and soapstock is rapidly formed, promptly cooling said mixture to a temperature below 100 F. and which retards the saponification of neutral oil, maintaining said mixture in its cooled condition for sufficient time to provide for color removal and thereafter promptly separating said soapstock, including reacting color impurities from said neutral oil while at a temperature sufficient to facilitate such separation.

2. The process of refining animal and vegetable oils containing free fatty acids, which comprises, mixing an alkaline refining reagent with said oils at a temperature sufficiently high to prevent the formation of a stable emulsion, whereby said free fatty acids are substantially completely neutralized and a separable mixture of oil and soapstock is rapidly formed, promptly cooling said mixture to a temperature below 100 F. and which retards the saponification of neutral oil, maintaining the oil in its cool condition for a period of time sufficient to permit color reduction and thereafter separating said soapstock from said neutral oil at a temperature which facilitates separation for the particular oil being refined.

3. The process of purifying animal and vegetable oils, containing free fatty acids and coloring matter, which comprises, rapidly heating said oil to an emulsion breaking temperature for the particular oil being refined, mixing an alkaline refining reagent with said heated oil before substantial setting of the color of the oil has been effected, whereby a separable mixture of oil and soapstock is rapidly formed, promptly cooling saidmixture to a temperature which minimizes the saponification of neutral oil, maintaining the oil in its cool condition for a period of time sufficient to permit color reduction and thereafter within a brief period rapidly heating said mixture to a temperature facilitating centrifugal separation thereof and centrifugally separating said soapstock'from neutral oil.

4. The process of refining animal and vegetable oils containing fnee fatty acids and coloring matter, which comprises, mixing an alkaline refining reagent with said oils at a temperature sufliciently high to rapidly produce a separable mixture of oil and soapstock resulting from the neutralization of said free fatty acids, promptly cooling said mixture to a temperature below 100 F. and sufiiciently low to minimize saponification of neutral oil, maintaining said mixture in a cooled'condition for a brief period and in sufiicient state of movement to prevent'stratification of said soapstock and provide for the removal of color impurities from the oil, and thereafter separating the soapstock from neutral oil while at a temperature sufiicient to facilitate such separation.

mixture of oil and soapstock resulting from the neutralization of said free fatty acids, promptly cooling said mixture to a temperature below 100 F. and sufliciently low to prevent substantial saponification of neutral oil, maintaining said mixture in a .cooled condition and in sufficient state of movement to prevent stratification of said soapstock and provide for the removal of color impurities from the oil by said alkaline refining reagent, and thereafter centrifugally separating said soapstock from said 011 at a temperature which facilitates said centrifugal separation.

6. The process of refining animal and vegetable oils containing free fatty acids and coloring matter, which comprises, mixing an alkaline refining reagent with said oils at a temperature sufficiently high to rapidly produce a separable mixture of oil and soapstock resulting from the neutralization of said free fatty acids, promptly cooling said mixture to a temperature sumciently low to minimize saponification of neutral oil, maintaining said mixture in a cooled condition and in sufiicient state of movement to prevent stratification of said soapstock for sufficient time to provide for the removal of color impurities from the oil by said alkaline refining reagent,

and thereafter rapidly heating said mixture to a temperature which will facilitate centrifugal separation thereof and promptly centrifugally separating said soapstock from said oil.

7. The process of refining animal and vegetable oils containing free fatty acids, which comprises, rapidly mixing an alkaline refining reagent with said oils at a temperature sufficiently high to rapidly produce a separable mixture of oil and soapstock resulting from the reaction of said reagent with said free fatty acids, promptly cooling said mixture to a temperature below 100 F. and which will minimize saponification of neutral oil by said reagent, maintaining said mixture in its cooled condition for a period sumcient to permit color reduction and thereafter promptly centrifugally separating said soapstock from said 011 at a temperature which facilitates said centifugal separation for the oil being refined.

8. The process of refining-animal and vegetable oils containing free fatty-acids, which comprises, mixing an alkaline refining reagent in proper proportions with said oils at a temperature sufliciently high to rapidly produce a separable mix ture of oil and soapstock, cooling said mixture before substantial saponification of neutral oil to a temperature which will minimize saponification of neutral oil, maintaining said mixture in its cooled condition for a period sumcient to permit color reduction and thereafter promptly centrifugally separating said soapstock from neutral oil and heating said mixture during sepaq ration to a temperature facilitating said centrifugal separation.

9. The process of refining animal and vegetable oils containing free fatty acids and color impurities, which comprises, rapidly heating a stream of said oil to a temperature sufficient to quickly produce a separable mixture of oil and soapstock when a stream of alkaline refining reagent is mixed with'said oil, mixing said. stream of reagent with said stream of oil before the color has been set in said oil by said heating to form a stream of a mixture containing oil and soapstock,

said reagent to a temperature sufiiciently low to minimize further saponification of neutral oil,

maintaining said stream of cooled mixture in a state of. movement sufficient to prevent stratification of said soapstock while color materials are being reacted by, saidr'efining reagent and comat least partially remove gums and containingfree fatty acids, which comprises, rapidly mixing an alkaline refining reagent with said oils at a temperature sufiiciently high to rapidly produce a separable mixture of oil and soapstock resulting from the reaction of said reagent with said free fatty acids, promptly cooling-said mixture to a temperature below 100 and which will minimize saponification of neutral oil by said reagent, maintaining saidmixture in its cooled condition for a period suflicient to permit color reduction and thereafter promptly centrifugally separating said soapstock from said oil at a temperature which facilitates said centrifugal separation for the oil being refined.

11. The process of refining animal and vegetable oils containing free fatty acids and gums, which comprises, rapidly mixing a degumming reagent with said oil to precipitate said gums, promptly centrifugally separating the precipitated gums from said oil while said oil is at a temperature sufficiently high to facilitate said separation, rapidly mixing an alkaline refining reagent with the separated oil before cooling the same and at a temperature below 100 F. and

sufliciently high to-rapidly produce a separable mixture of oil and soapstock resulting from the reaction of said reagent with said free fatty acids, promptly cooling said mixture to a temperature which will minimize saponification of neutral oil by said reagent, maintaining said mixture in its cooled condition for a period sufiicient to permit color reduction and thereafter promptly centrifugally separating said soapstock from said oil at a temperature which facilitates said centrifugal separation for the oil being refined.

12. The process of refining animal and vegetable oils containing free fatty acids, which comprises, rapidly mixing an alkaline refining reagent with said oils in the presence of a saponification and entrainment inhibitor and at a temperature suificiently high to rapidly produce a separable mixture of oil and-soapstock resulting from the reaction of said reagent with said free fatty acids, promptly cooling said mixture to a temperature which will minimize saponification of neutral oil by said reagent, maintaining said mixture-in its cooled condition for a period sufficient to permit color reduction and thereafter promptly centrifugally separating said soapstock from said oil at a temperature which facilitates said centrifugal separation for the oil being refined.

13. The process of refining animal and vegetable oils which have been previously treated to at least partially remove gums and containing free fatty acids, which comprises, rapidly mixing an alkaline refining reagent with said oils in the presence of a saponification and entrainment inhibitor and at a temperature sufiiciently high to rapidly produce a separable mixture of oil and soapstock resulting from the reaction of said"re-. agent with said free fatty acids, promptly cooling color reduction and thereafter promptly centrif ugally separating said soapstock from said oil at a temperature which facilitates said centriff ugal separation for the oil being refined.

14. In the art of continuously removing free'f 10 fatty acids and color impurities from-animal and vegetable oils wherein an alkaline refining reagent is admixed with said oils to substantially completely neutralize the free fatty acids contained therein and to form soapstock and wherein the mixture is conditioned for the step of centrifugal separation with the aid of heat sufliciently high to break any emulsion which may result from said admixing, the improvement which comprises promptly cooling saidmixture below the emulsion breaking temperature of the oil being treated and which retards the saponification of neutral oil, maintaining said mixture in its cooled condition for a period sufliciently long to permit color reduction and thereafter continuously introducing the mixture of refined oil, soapstock and color impurities to a centrifugal separator and continuously separating the soapstock and said color impurities from the refined oil while the said mixture is in its said nonemulsified condition whereby to facilitate such separation.

comprising the continuous advancement, as a stream, of the thus conditioned mixture of oil and soapstock through a color reduction zone where the mixture is maintained for a period sufliciently long to permit color-reduction'by the softened soapstock particles combining with color impurities, preventing the continued rise in temperature of the mixture as it passes through said zone by rapidly cooling the mixture below the emulsion breaking temperature of the oil being treated and to an extent whereby to minimize refining losses of neutral oil during the color reduction step and thereafter continuously introducing the mixture to a centrifugal separator and continuously separating the soapstock and color impurities from the refined oil under such temperature conditions as to facilitate such separation.

16. The process of refining animal and vege-- improvement which comprises cooling said mixture to a temperature below 100 F. and which retards the saponification of the neutral oil by an increase in the temperature of said admixture, maintaining the mixture in its relatively cool condition for a period of time sufficient to permit the soapstock particles to combine with impurities contained in said oil and thereafter introducing the mixture of refined oil, soapstock and combined impurities to a centrifugal separator and continuously separating the soapstock and combined impurities from the refined oil while the mixture isat a temperature sufficient to facilitate such separation.

17. The process of refining animal and vegetable oils for the removal of free fatty acids therefrom comprising the steps of admixing an alkaline refining reagent with said oil in a mixing zone to effect substantial neutralization of said free fatty acids and to form soapstock, conditioning said mixture for centrifugal separation with the aid of heat sufficient to break any emul-'- sion which may result from said admixing, advancing the thus conditioned mixture from the mixing zone to a color reduction zone, cooling the mixture to a temperature below 100 F. and which retards saponification of the neutral oil and maintaining the same in its cooled condition for a period of time sufiicient to permit substantial color reduction and thereafter subjecting the mixture to centrifugal separation for the separation of the soapstock and combined impurities from the neutral oil while said mixture is in a condition for said separation.

18. The process of refining animal or vegetable oils for the removal of impurities therefrom, wherein a refining reagent is mixed with said oil to form foots, and wherein the mixture is conditioned for the step of centrifugal separation with the aid of heat sufficiently high to facilitate such separation, the improvement which comprises cooling said mixture of impurities in the form of foots and said oil, to a degree which will retard attack upon the neutral oil, maintaining the mixture of foots and said neutral oil in its relatively cool condition for a period of time suflicient to permit said foots to combine with impurities in said oil, and thereafter introducing the mixture of refined oil, foots and said com.- bined impurities, to a centrifugal separator and continuously separating the foots and combined impurities from the refined oil whilethe mixture is at a temperature sumcient to facilitate such separation,

19. The process as defined in claim 18 in which the refining reagent comprises acid.

20. The process as defined in claim 18 in which the mixture is continuously cooled during its flow through the system to a degree below 100 F.

21. The process as defined in claim 18 in which the mixture is continuously reheated following the cooling thereof, to a degree sufiicient to lower the viscosity of therefined oil and thereby facilitained in said oils to convert the oil from its break characteristics to a non-break condition, cooling the mixture of oil and foots to a degree which will minimize attack-upon the oil and for a sufficient time to permit said foots to combine with other impurities contained in the oil and thereafter subjecting the mixture to the action of centrifugal separation to separate the foots from the resultant non-break oil.

23. The process as defined in claim 22 in which the mixture is heated to an emulsion breaking temperature prior to said cooling step.

24. A process for treating animal and vegetable oils to remove at least some of the impurities therein contained which comprises the steps of introducing a refining reagent capable of precipitating said impurities in a condition where the same may be centrifugally separated from the resultant purified oil, continuously passing the resultant mixture through a cooling zone and there lowering the temperature to a. degree which will minimize attack upon the oil and for a suflicient time to effect further segregation of the impurities, and thereafter subjecting the segregated impurities and the purified oil to centrifugal separation.

25. The process as defined in claim 24 in which the mixture is subjected to an emulsion breaking temperature prior to the cooling thereof.

26. The process as defined in claim 24 in which the mixture is reheated to facilitate centrifugal separation.

BENJAMIN CLAYTON. 

